Background

APC is an ubiquitin ligase with multi subunits. It ubiquitinates substrates (e.g. cyclin B1 and secrin) and make them the targets for degradation with 26s proteasome, resulting in initiation of anaphase and mitotic exit. [2]

In mitotic Xenopus oocytes, TAME competes with the Cdc20 C-terminal IR-tail for APC binding to inhibit APC-dependent proteolysis. [3] TAME also stabilizes cyclin B1via terminating ubiquitination prenaturally. It slows the unmodified cyclin B1 initial ubiquitination. In the presence of TAME, ubiquitinated cyclin B1 is not able to promote Cdc20 binding to the APC. [4]